Sift flour and salt together in a medium bowl. Set aside.

In a separate large bowl, using an electric hand mixer, thoroughly mix together butter, confectioner's sugar, and vanilla until smooth.

Stir in flour and salt mixture until dough forms. Add in nuts if desired.

Chill dough in the fridge for at least an hour.

Preheat oven to 400 degrees F.

Roll into 1 inch balls. Bake on an ungreased baking sheet for 10-12 minutes. Watch cookies carefully as they're quick to burn. Cookies are done when they're just slightly turning light brown - you'll think they need more time. Don't be fooled. Check the bottoms before you leave them in longer to be sure you're not burning them.

Remove from the oven, let cool until you can handle them comfortably, then roll in confectioner's sugar.

Let cool completely, then roll in sugar one more time.